Precision machine-tool



A. E. JERRAM. PRECISION MACHINE TOOL. APPLICATION FILED APR. 22. 1918.

Patented June 22, 1920.

4 SHEETS-SHEET l.

A.. E. JERRAM.

PRECISION MACHINE TOOL.

APPLICATION FILED AFR-22, 191a.

,344:,536. I Patented June 22, 1920.

4 SHEETS-SHEET 2.

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A. E. JERRAM.

PRECISION MACHINE TOOL. APPLICATION FILED APR. 22. 19M.

4 SHEETS-SHEET 4- Patented June 22, 1920.

UNITED STATES PATENT OFFICE.

ARTHUR ERNEST J ERRAM, OF LEIGESTERSHIR-E, ENGLAND.

PRECISION MACHINE-TOOL.

Application filed April 22,

To all whom it may concern:

Be it known that I, ARTHUR ERNEST J n1:- RAM, a subject of the King ofEngland, residing at Leicestershire, England, have invented certain newand useful Improvements in Precision ll/lachine-T ools, of which thefollowing is a specification.

This invention relates to a process and apparatus for making accurateprecision screws, such for example as are required for use as screwgages or as components of measuring devices.

Broadly speaking the improved process is one wherein two cutting toolsfor forming the screw threads are arranged to act on opposite ends of a.diameter of the work and each againsta different part of the threadcontour to the other, for example against opposite flanks of ascrewthread in order that the pressure each thus exerts against the workshall be almost entirely counterbalanced by the equal pressure of itscompanion situated nearly in the same plane and acting in the oppositedirection and therefore shall neither put any considerable bendingstress on the work nor set up any material side thrust against the work'holder or against the bearings in the machine in which the latter issupported.

dividing between the two cutters the work of taking a finishing cut overthe flanks and root of the thread the individual thrusts of each toolare approximately halved as compared with the single tool ordinarilyused and are thus reduced to the minimum compatible withiinishing theentire contour of the screw thread at one traverse. Furthermore, byallocating the finishing cut on each flank of a thread to a differentcutter the cutting edges can have the top rake that is required toenable the tool to cut the material efficiently and with a minimum ofthrust.

Furthermore this distribution and minimizing of the thrusts of cuttingenable work that is held in a chuck to be screwthreaded with greaterprecision than has been heretofore practicable. Prior to this inventionprecision screws such as screw gages have always been machined betweencenters supporting both ends of the work and the necessary slack toinsure a running fit on the centers is a source of trouble affectingboth the diametral and pitch meas urements and rendering uniformity oftem perature of work and machine more es- Specification of LettersPatent.

Patented June 22, 1920.

1918. Serial No. 230,088.

sential' than is necessary accordin to the preferred method of carrying(hit my process.

Heretofore screw-gages and the like have been made 1n machines in whichthe traversing motion of the cutter or of the mandrel was obtaineddirectly from a leadscrew which is well-known to be a device extremelydifficult to make accurately. The machine of the present invention isprimarily designed to secure extraordinary accuracy in the working ofthe complete machine, while the separate elements concerned do notrequire to be of anything more than the accuracy that is readilyobtainable coinnercially. A second object of the present invention isthe finishing of a maximum number of thread-gages with one sharpenlngand setting of the cutters so that the minimum amount of skilled laborshall be required. This result is secured by employing cutters of thecorrect form for cutting tools for steel to perform only the linefiliishing cuts along the contours of the screwthread which whensubmitted to their ac tion, is slightly above the finished size and hasbeen made accurate within what are known as commercial limits only. Theprincipal features of a machine constructed according to the presentinvention are :A rotary traversing mandrel combined wit-h a shaft foractuating it. and with two trains of reducing-gearing which two trainsare operative connections of a positive kind which connect the mandreland said shaft and are proportioned the one train to turn the mandrel atan angular velocity low in relation to that of the said shaft and theother train to impart a traverse to the mandrel of a linear velocity lowin relation to the peripheral velocity of that shaft; also as elementsin he traversing train, a wedge and a screw to propel the wedge; also anut iournaled in the wedge to effect the traverse of the wedge whileunder the of Fig. 1, hereinafter more particularly referred to; 1

Fig. 3 is an elevation of that portion of the machine which in the plan,Fig. 1, is the lower portion;

Fig. 4C is an elevation of part of what is the right-hand end of themachine in Fig. 1;

Fig. 5 is an enlarged view of part of what is shown on a smaller scalein Fig. 3 and with certain of the details in'section;

Fig. 6 is a section of wedge devices employed in Fig. 5, the sectionbeing taken on the line 6-6 of Fig. 5; and

Fig. 7 is a side elevation of Fig. 5 taken in the direction of thearrow, Fig. 5. Like letters and reference numerals indicate like partsthroughout the drawings.

The machine (see primarily Figs. 1 and 2) comprises a main frame F withbearings l and 2 in which is a parallel rotary traversing mandrel M. Atthe forward end of the mandrel is a collet chuck C or other means to fixthe work securely to it.

1 A worm-wheel V7 is provided on the mandrel M by which the mandrel canbe turned and through which the mandrel can move endwise, they beingprevented from having a rotatory motion one in relation to the other, bypins P P parallel with the mandrel and carried spaced well apart on acrosshead K attached rigidly thereto, and sliding through holes in theworm-wheel toward opposite ends of a diameter of the latter. A worm w isprovided to drive the worm- Wheel Two springs S S are interposed betweenthe worm-wheel and the cross-head K and act to press the mandrel in anendwise direction, 2'. c. the direction indicated bythe arrow in Figs. 1and 2 toward the rear of the machine and the worm-wheel forwardly upagainst a thrust bearing T abutting against the" part 2 of the mainframe. The thrust bearing T is preferably a ball thrust. The springs aresuficiently strong to insure that the tail end MT of the mandrel shallalways bear against the face of the wedge J hereinafter described. 7

To move the mandrel endwise against the resistance of the springs S awedge J is provided which slides across the rear end of the mandrel upona slide-way SlV on the main frame, the slideway being slightly angled,as shown inFig. 1, in relation to the mandrel axls. The wedge J bearsagainst the fiat-ended tail MT of the mandrel M to move it endwise inthe mandrel bearings 1, 2. This wedge is driven by a lead-screw LSarranged parallel to the slide way SWV. A nut N on'the wedge is engagedV by the.leadscrew; it is held against'end wise movement in relation tothe'wedge (by it is indicated as being merely contiguous to the end ofsaid wedge) in which wedge. an extension N of the nut is journaled asshown in Fig. 1. This nut is provided with an arm NA. A stationaryeambar B is fixed to the rear of the machine-frame F and along thiscam-bar the said arm NA travels in the movement of the wedge J so as tokeep the arm and its nut from turning or to impart to them a smallangular adjustment, as required. This small angular adjustment isemployed to correct minutely the relationship between the travel of thewedge J and the rotation of the lead-screw LS so that by suitablyshaping the top edge of the cam-bar B the small periodic or other errorsexistent in all machine parts such as the lead-screw or the wedge can beaccurately and readily compensated for.

There is an antifriction rollerr on the arm to bear on the cambar B, andon the outer end of the arm a weight wt which keeps the arm NA pressedtoward the roller and keeps the roller down on the bar.

The cam-bar is preferably secured to a facing on the machine-frame byscrews at either end and in such manner that either end of the bar maybe raised or lowered to compensate for total error of traverse or it maybe to enable metric threads to be cut in a machine initially arrangedfor English threads, or vice versa. In certain cases the cambar mighteven be a'simple bar with a straight upper face inclined slightly out ofthe horizontal. I j

The wedge J is a solid and long one, with an easy taper upon it and twodirectlyopposite acting faces J J one J acting against an fabutting faceof the slideway SlV aforesaid and the other J 2 against the tailMT'of.the mandrel M; the taper is about one in ten, consequentlyinaccuracies in the pitch of the lead-screw LS are minimized to aboutone-tenth, and small errors that can be discovered in resultant work canbe practically eliminated by suitably shaping in a comparatively roughand ready manner the cam-bar B acting on the arm NA of the nut N abovereferred to, so as to correct not only inaccuracies in the leadscrew butalso inaccuracies in the wedge J.

The shaft 'w a on which is the beforementioned worm w for rotating themandrel, is driven at its end 10 (preferably by r a self-adjustingcoupling of any suitable construction) from a countershaft not shown inthe drawings, provided with areversing device, and the other w end ofthe 'worm-shaft carries a gear-pinion 3 9 adapted to engage achange-gear wheel 19 carried on a rotating sleeve 29 that is providedwith a gear-pinion 10* meshing with a gear-wheel 79 which latter isfixed to the lead-screw LS that propels the wedge J.

The change-gear wheel sleeve 19 is mounted on an arm 9 that can beadjusted about the axis of the lead-screw as in a lathe, so as tosupport change wheels 21 and bring different sizes of these wheels intoaccurate mesh with the gear-pinion p 011 the worm shaft. The rotation ofthe worm-wheel N that turns the mandrel M being effected slowly by therelatively fast-turning worm 'w fixed on the shaft w w, and thetraversing of the mandrel (that combined with the turning, generates thespiral of the screw thread) being effected slowly by reducinggear 29 p p39 leadscrew LS and wedge J, it will be seen that just as the rotarymovement of W and the traversing move ment of M are reduced in relationto the angular velocity of the shaft to 'w so also will be reduced theeffect on the rotation of V and the traverse of M of any error in thetransmission of the angular velocity of 10 e0 aforesaid to the partsultimately driven by it. Furthermore, the change-gear (such as p p p 79for the different pitches of screwthread being high speed and acting asa reducing-gear in synchronizing both the turning and traversingof themandrel, it follows that ordinary commerciallycut gears can be usedwithout materially affecting the accuracy of the work, for er rors inthe gears will be reduced down before they get as far as the lead-screwspindle, to dimensions so small as even upon the finest work to be negliible.

Inasmuch as the springs b as aforesaid are sufficiently strong toprevent the tail end MT of the mandrel M from ever leaving the face J ofthe wedge J, the traversing movement of the mandrel, no less than itsmovements of rotation may be considered as under positive control, forwhile the devices for rotating the mandrel are in the strictest sensepositive, the gear for traversing the mandrel is strictly positive whenthe mandrel is being thrust toward the front of the machine and thescrew is being formed.

Referring now to Figs. 3, 5, 6 and 7, cut ter-carrier-bars or carriers 3and 4 are set on opposite sides of the chuck C (Fig. 3) so as to be 180degrees apart and radial and perpendicular to the mandrel-axis. Thecutters 3 4 for cutting the thread are circular form turning-toolspreferably each cutting on one flank of the screwthread only, and eachis mounted with the center line of its cutting edge in line with theaxis of the cutter-carrier, which carrier is cylindric. A saddle foreach cuttercarrier is provided and may be constituted by a substantiallever L or L appropriated to it and pivoted at L or L respectively tothe main frame F at a point much nearer the left-hand end of each leverthan to the other. The longer ends Z Z of these levers are capable of aslight movement toward and away from one another, like a pair of jaws.Each cylindric cutter-carrier 8 or f is adjustable to slide endwisealong and also to turn in a bearing or bore in its saddle arrangedradially to the mandrelaxis, and it can be clamped by clamp-screws Z(see Fig. 5) or Z in the position to which it is thus adjusted. Onecutter-carrier 4: (see also Fig. 5) is directly mounted in the lever If,the other 3 is in a carriage L form ing part of the lower arm of thelever L but capable of being moved in relation to thelatter along guidebars G on the lever that are parallel to the mandrelaxis. This latteradjustment is to enable the cuttercarrier with its cutter to be set tosuit the pitch of the thread being cut, and is controlled by a suitablemicrometer m which actuates an adjusting wedge L bearing against aprojection G on the upper guide bar G Clamping bolts are provided at Q2g to lock the levers in adjusted position while a cut is being taken.

Of these bolts, passes through a plain hole in a triangular clamp-plate0 into a threaded hole in the frame F of the machine (see Figs. 5 and7). The bolt-head bears on the clamp-plate near one end thereof, and theouter end of the clamp-plate c rests on a fixed extension or stud s inthe frame F. The corners 0 and c of 0 rest respectively on the levers Land L"; so, by screwing in the bolt the levers L and L are pressed bythe clamp-plate 0 toward the frame, at points near to the lever pivots LL The belt controls a similar clamp 0 which by its corners 0 and c bearson the levers L L at points remote from their pivots L and L The bolt 7has upon it a box nut 9 the inner end of which bears on the side of thelever L a similar bolt 9 has a similar box nut 9 which bears on the sideof the lever L A wedge O and a micrometer adjustment m therefore areprovided to move the cutters toward and away from one another byaltering the distance between the adjacent longer ends Z Z of thesaddles or levers L L aforesaid. The wedge is kept by a spring incompression, m against the end of the micrometer device m and the sidesof the wedge bear against half-bushes Z Z" which are seated in the endsof the longer arms Z Z A spring 0 in compression acts, see Figs. 3 and5, between the adjacent heels or arms of the said levers L L to keep theouter arms thereof pressed toward the afore said wedge O.

The cutter-carriers 3 and 4 are adjustably rotatable in their bearingsto set the cutters to suit the angle of thread to be cut, and they arearranged to slide in the same bearings to suit different diameters ofscrew gages or other work indicated at WK in F igs. 3 and 5. Therotation of the cuttercarriers 3 and 1 in their bearings is controlledby an arm 80 or 40 fixed to each and actuated by an adjusting screw 31or 421 and spring-plunger 32 or 412. After the cutters have been thusangled correctly, the endwise adjustment of the cutter-carriers can beeffected by means of standard distancepieces 33 43. Against the outerend of each distance-piece rests a screw 4A in the carrier 40 and 3&- inthe carrier 30. The inner end of the distance-piece 33 rests in a seat35 formed in the carriage L as shown. By a choice of distance-pieces ofsuitable length the situation of the carriers 3 and 4 can be adjusted todefinite positions to suit particular diameters of screws as regardstheir endwise movement in relation to the levers in which they areborne.

An independent fine axially-endwise adjusting device for the carrier 4:consists of a micrometer-screw-actuated wedge 45 for adjusting a slidingabutment 46 against which the inner end of the distance-piece 13 bears;this is provided in the lever L1 only, so that the carrier 4 and itscutter P may be adjusted to and from the work to precisely the samedistance as that of the cutter 3 from the exact center of the work.

The clamping bolts Z Z clamp the cuttercarriers in their bores in thepositions into which they have been radially and rotatably adjusted.

The saddles or levers L L themselves are finally clamped down to theframe F by the clamping devices 9 9 Q2 aforesaid which engage eachsaddle at three points (see Fig. 3) so. that no distortion ordisplacement of the saddle can take place from the action of the clamps.

As the cutter-carriers and the saddles or levers on which they aremounted are all rigidly looked after adjustment, there are no slacks oroil films anywhere in the cuttersupporting devices that vary and mayalter the cut during the actual cutting of the screwthread. 1

' The Work in the collet chuck C is preferably gripped on two parts ofthe shank of the screw or gage so as in effect to secure it rigidly tothe mandrel M before mentioned.

In the case of cutters, with widely-spaced teeth, these driving-shaftsshouldpreferably be so geared together-as to insure that the respectiveteeth of each cutter act on the work simultaneously with the respectiveteeth on the other cutter. 7

that I claim as my invention and desire to secure by Letters Patentis 1. A machine provided with a rotary traversing mandrel combined witha shaft and twoseparate trains of reducing gearing,

which two trains are connected separately from one another to the saidshaft, and are operative'connections of a positive kind connecting themandrel and sald shaft and are proportioned the one train to turn theman- 'linear velocity low'in relation to the peripheral velocity. ofthat shaft.

2. The subject-matter of preceding claimingclause No. '1, plus twocutting-tools adjustably mounted in supports on the machine-frame andsituated atopposite sides of the mandrel-end to minimize unbalancedcross-thrust on it. V

3. The subject-matter of preceding claiming-clause No. 1, plus twocutting-tools adjustably mounted in'supports on the machine-frame andsituated at opposite sides of the mandrel-end to minimize unbalancedcross-thrust on it andv locking means for locking the adjusted tools andtheir supports in relation to the machine-frame after their adjustmentin relation thereto.

4:. The subject-matter of preceding claiming-clause No. 1, plus twocutting-tools adjustably mounted in supports on the machine-frame andsituated at opposite sides of the mandrel-end to minimize unbalancedcross-thrust on it and so as to be adjustable along radii of the worktoward and away from it and adjustable rotarily about their own axeswhich are normal to the axis of the Work.

5. Thesubject-matter of preceding claiming-clause No. 1, plus twocutting-tools adjustably mounted in supports on the machine-frame andsituated at opposite sides of the mandrel-endto minimize unbalancedcross-thrust on it, and so to be adjustable along radii of the worktoward and away from it and adjustable rotarily about their own axeswhich are normal to the axis of the work, and locking means for lockingthe adjusted tools and their supports in relation to themachineframe'after their adjustment 110 in relation thereto. 7

6. The subject-matter of preceding claiming-clause No. 1, plus twocutting-tools adjustably mounted in supports on the machine-frame andsituated at opposite sides of 115 the mandrel-end tominimize unbalancedcross-thrust on it and so as to be adjustable along radii of the worktoward and away from it and adjustable rotarily about their :own axeswhich are normal to the axis of the chine-frame and situated at oppositesides of the mandrel-end to minimize unbalanced cross-thrust on it andso as to be adjustable along radii of thework toward and away from itandadjustable rotarily about their own axes which are normal to the axis ofthe work, means to adjust one of the cutters in a direction parallel tothat of the work-axis and locking means for locking the adjusted toolsand their supports in relation to the machine-frame after theiradjustment in relation thereto.

, 8. In a machine tool the combination of a plurality of cutterssupported on opposite sides of the work, each cutter to act against aface of the thread contour different from the face against which thecompanion cutter acts, one cutter adjustable in its support in adirection parallel to that of the axis of the work and independently ofthe other, and means for adjusting them simultaneously toward and awayfrom the work.

9. In a machine tool the combination of two cutters supported onopposite sides of the work one adjustable in its support in a directionparallel to that of the. axis of the work and independently of theother, means for adjusting them simultaneously toward and away from thework and means whereby one of the cutters is adjustable along aradius-of the work toward and away from the work independently of itscom panion.

10. In a machine tool the combination of a rotary traversing mandrel,bearings in which it is movable endwise as well as rotatably, adriving-shaft, a train of reducing gearing which forms an operativeconnection between said mandrel and driving-shaft and turns the formerat an angular velocity lower than that of the latter, a wedge with twolong faces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedgefaces against which themandrel tail abuts and a train of reducing-gearing forming an operativedriving-connection to propel the wedge and so proportioned that. thelinear movement thereby imparted to the wedge shall be low in relationto the peripheral velocity of the shaft from which said reducing gear isactuated.

11. In a machine tool the combination of a rotary traversing mandrel,hearings in which it is movable endwise as well as retatably, adriving-shaft, a train of reducing gearing which forms an operativeconnectionbetween said mandrel and driving-shaft and turns the former atan angular velocity lower than that of the latter, a wedge with two longfaces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead-screw, and a train of reducing-gearing which forms an operativeconnection between said lead-screw and the said driving-shaft of thelead-screw and turns the lead-screw at an angular velocity lower thanthat of its driving-shaft.

12. In a machine tool the combination of a rotary traversing mandrel,hearings in which it is movable endwise as well as rotatahly, a drivingshaft, a train of reducing-gearing which forms an operative connectionbetween said mandrel and drivingshait and turns the former at an angularvelocity lower than that of the latter, a wedge with two. long facesagainst one of which faces the tail of the traversing mandrel abuts at aright angle, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe leads-crew, a train of reducing-gearing which forms an operativeconnection between said lead-screw and the said driving-shaft of thelead-screw and turns the lead-screw at an angular velocity lower thanthat of its driving shaft, a worm-wheel coaxial with the traversingmandrel and in sliding but relatively non-rotary connection therewith,and a wornrshaft geared with the worm-wheel and. set in bearings in themachine-frame with its axis parallel to the axis of the lead-' screw.

13. in a machine tool the combination of a rotary traversing mandrel,hearings in which it is movable endwise as well as rotatably, adriving-shaft, a train of reducinggearing which forms an operativeconnection between said mandrel and driving-shaft and turns the formerat an angular velocity lower than that of the latter, a wedge with twolong faces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedgefaces against which themandrel tail abuts, a

lead-screw in fixed bearings, drivin -shaft for the lead-screw, a trainoi? reducing-gearing which forms an operative connection between saidlead-screw and the said drivingshaft of the lead-screw and turns theleadscrew at an angular velocity lower than that of its driving-shaft, anut mounted on the Jvedge and rotatable on it but held against endwisemovement in relation to the wedge and threaded to the lead-screw, va camstationary alongside the line in which the nut moves with the wedge, anda lever extending from the nut and means to keep said lever pressedagainst the cam while it is" drawn along the cam in the movement of thenut. 1 1

14. In amachine tool the combination of a' rotary traversing mandrel,bearings in lowerthan that of the latter, avwedge with two long facesagainst one of which faces the tail of the traversing mandrel abuts at aright angle, yielding means to press the said tail against'the wedge, aslideway constitut- 7 mg an abutment along which the wedge slides andwhich at an. angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead-screw, a train of reducing-gearing which forms an operativeconnection between said leadscrew and the said driving-shaft of thelead-screw and turns the lead-screw at an angular velocity lower thanthat of its driving-shaft, a nut mounted on the wedge and rotatable onitbut held against endwise movement in relation to the wedge, andthreaded to the lead-screw, a cam stationary alongside the line in whichthe nut moves with the wedge, and a lever extending from the nut andmeans to keep said lever pressed against the cam while it is drawn alongthe cam in the movement of the nut.

In a machine tool the combination of a rotary traversing mandrel,bearings in which it is movable endwise as well as rotatably, adriving-shaft, a train of reducinggearing which forms an operativeconnection between said mandrel and driving-shaft and turns the formerat an angular velocity lower than that of the latter, a wedge with twolong faces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides andwhichis at an angle to that one of the long wedgefaces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead'screw, a train of reducing-gearing which forms an operativeconnection between said lead-screw and the said driving-shaft of thelead-screw and turns the lead-screw at an angular velocity lower thanthat of its driving-shaft, a nut mounted on the wedge and rotatable onit but held against. endwise movement in relation tothe wedge andthreaded to the leadscrcw, a cam stationary alongside the line inwhichthe nut moves with the wedge, a lever extending from the nut andmeans to keep said. lever pressed against the cam while it is drawnalong thecam in the movement of the nut and two cutting-tools adof themandrel-end to minimize unbalanced cross-thrust on it. a

'16. In a machine tool the combination of a rotary traversing mandrel,hearings in which it is movable endwise as well as rotatably, adriving-shaft, a train of reducing-- gearing which forms an operativeconnection between said mandrel and'driving-shaft and turns the formerat anangular velocity lower thanthat of thelatter, a wedge with two longfaces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway "constituting an abutment along which the wedge slides andwhich" is at an angle to that one'of the long wedgefaces against whichthe mandreltail abuts, a lead-screw in fixed bearings, a driving-shaftfor the lead screw, a train of reducing-gearing which forms an operativeconection between said lead-screw and the said drivingshaft of the:lead-screw and turns' the leadscrew at an angular velocity lower thanthat of its driving-shaft, a nut mounted on the wedge and rota-tableon'it but held against endwise movement in relation to the wedge andthreaded to the lead-screw, a cam" stationary alongside the line inwhich the nut moves with the wedge, a: lever extending from the nut andmeans to keep said lever pressed against the cam while it is drawn alongthe cam in the movement of the nut, and cutter-carrier bars borne by themachine frame 180 apart and radial and perpendicular toethe mandrel-axisand rotatable and endwise movable in relation to their supports on-themachine-frame.

17, In a machine tool' the combination of a'rotary traversing mandrel,bearings in which it is movable endwise as well as rotably, adriving-shaft, a train of reducing gearing which forms an operativeconnection between said mandrel and drivingshaft and turns the former atan angular velocity lower than that of the latter, a wedge with two longfaces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tailagainst the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe leadsscrew, a train of reducing gearing which forms an opera-v tiveconnection betweenvsaid lead-screw and the said. driving-shaft of thealead-screw and turns the lead-screw at an angular velocity lower, thanthat of its drivingsh aft,-a nut mounted on'the wedge and r0- tatable onit but held against endwise movement in relation to the wedge andthreaded to the lead-screw, a cam stationary along-V side the line inwhich the nut 'moves with the wedge, a lever extending from the nut andmeans to keep said lever pressed against the cam while it is drawn alongthe cam in the movement of the nut, two cutting-tools adjustably mountedin supports on the machineframe and situated at opposite sides of themandrel-end tominimize unbalanced cross-thrust on it, a saddle carryingeach cutting-tool and pivoted by one end of the saddle to themachine-frame, both saddles pivoted at one side of the mandrel andextended from their pivots past the mandrel to its opposite side, andclamps for the saddles. v

18. In a machine tool the combination of a rotary traversing mandrel,hearings in which it is movable endwise as well as rotatably, adriving-shaft, a train of reducing gearing which forms an operativeconnection between said mandrel and driving-shaft and turns the formerat an angular velocity lower than that of the latter, a wedge with twolong faces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedge-faces against whichthemandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead-screw, a, train of reducing gearing which forms an operativeconnection ,be

' ween said lead-screw and the said drivingshaft of the leadscrew andturns the leadscrew at an angular velocity lower than that of itsdriving-shaft, a nut mounted on the wedge and rotatable on it but heldagainst endwisel movement in relation to he wec ge and threaded to thelead-screw, a cam stationary alongside the line in which the nut moveswith the wedge, a lever extending from the nut and means to keep saidlever pressed against the cam while it is drawn along the cam in themovement of the nut, two cutting-tools adjustably mounted in supports onthe machine-frame and situated at opposite sides of the mandrelend tominimize unbalanced cross-thrust onit,asaddle carrying each cutting-tooland pivoted by one end of the saddle to the ma chine-frame, both saddlespivoted at one side of the mandrel and extended from their pivots pastthe mandrel to its opposite side,

clamps for the saddles, a carriage interposed between one saddle and onecutter, to support the'cutter adjustably along the length of the mandrelin relation to that saddle, and guides onsaid saddle for the carriagethat are parallel to the mandrelazris. r

19. In a machine tool the combination of a rotary traversing mandrel,bearingsin which it is movable 'endwise as wellas rota-tably, adriving-shalt, a train of reducing gearing which forms an operativeconnection between said mandrel and driving-shaft and turns the formerat an angular velocity lower than that of the latter, a wedge with twolong faces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslidcway constituting an abutment along which the wedge slides and whichis at an angle to that one of the longv wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead-screw, a train of reducing gearing which forms an operativeconnection between said leadscrew and the said driving-shaft of theleadscrew and turns the lead-screw at an angular velocity lower thanthat of its drivingsh'aft, a nut mounted on the wedge and retatable on.it but held against endwise move ment in relation to the wedge andthreadec to the lead-screw, a cam stationary alongside the line in whichthe nut moves with the wedge, a lever extending from the nut and meansto keep said lever pressed against the cam while it is drawn along thecam in the movement of the nut, two cuttingtools adjustably mounted insupports on the machine-frame and situated at opposite sides of themandrel-end to minimise unbalanced cross-thrust on it, a saddle carryingeach cuttingtool and pivoted by one end of the saddle to the machine me,both saddles pivoted at one side of the mandrel and extended from theirpivots past the mandrel to its opposite side, yielding means whichthrust the saddles tow one another at that side of the mandrel Jnichfaces away from the saddle pivts, and a wedge between the approachingportions the saddles which is adjustable in direction perpendicular tothe plane of their approach, and clamps for the saddles.

20. In a machine tool the combination of a rotary traversing mandrel,bearings in which it is movable endwise as well as retatably, adriving-shaft, a train of ing gearing which forms an operativeconnection between said mandrel and drivi shaft and turns the former atan angular velocity lower than that of the l2l'"i1\fil,' a wedge withtwo long faces against one oi which faces the tail of the traversingmandrel abuts, yielding means to press the sah tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one 0% the long wedge-faces against which themandrel tail abuts, a lcad scrcw in fixed bearings, a driving-shaft forthe lead-screw, a train of reducinggearing which forms an operativeconnection between said leadscrew and the said driving-shaft of theleadscrew' and turns the lead-screw at an anguone saddle and one cutter,to support the are parallel to the mandrel-axis.

of the mandrel-end to minimize unbalanced cross-thrust on it, a saddlecarrying each cutting-tool and pivoted by one end of the saddle to themachine-frame, both saddles pivoted atone side of the mandrel andextended from their pivots past the mandrel to its opposite side,yielding means which thrust the saddles toward one another at that sideof the mandrel which faces away from the saddle pivots, a wedge betweenthe approaching portions of the saddles which is adjustable in adirection perpendicular to the plane of their approach, clamps for thesaddles, a carriage interposed between cutter adjustably along thelength of the mandrel in relation to that saddle, and guides on saidsaddle for the carriage that 21. In a machine tool the'combination of arotary traversing mandrel, hearings inwhich it is movable endwise aswell as .rotatably, a drivingshaft, a train of reducing gearing whichforms an operative connecvelocity lower than that of the latter, a

7 Wedge with two long faces against one of which faces the tail of thetraversing mandrel abuts, yielding means to press the said tail againstthe wedge, a slide-way consti- -tuting an abutment along which the wedgeslides and which is at an angle to that one of the'long wedge-facesagainst which the mandrel tail abuts, a lead-screw in fixed bearings, adriving-shaft for the lead-screw a train of reducing gearing which formsan operative connection between said leadscrew and the saiddriving-shaft of the lea dscrew and turns'the lead-screw at an angularvelocity lower than thatfof its drivingshaft, a nut mounted on the wedgeand rotatable on it but held against endwise movement in relation to thewedge and threaded to the lead-screw, a cam stationary alongside theline in which the nut moves with the wedge, a lever extending from thenut and means to keep said lever pressed against the cam while it isdrawn along the cam in the movement of the nut, two cutting-toolsadjustably mounted in supports on the machine-frame and situated atopposite sides of the mandrel-end to minimize unbalanced cross-thrust onit, and locking means for locking the adjusted 'toolsand theirsupports'in relation to themachi'ne-frame after their adjustmentinrelation thereto.

22, In a machine tool'the combination of a rotary traversing mandrel,bearingsin which it ismovable endwise as well as rotatably, adriving-shaft, a train of reducing gearing'which forms an operativeconnection between said mandrel and drivingshaft and turns the former atan angular velocity lower than that of the latter, a wedge with two longfaces against one of which faces the tailof the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslide-way constitutingan abutment along whichthe wedge slides andwhichis at an angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead-screw,

ment in relation to the wedge and threaded to the lead-screwgaicamstationary alongside the line' in whichthe nut moves with the wedge, alever extending from the nut and means to keep said lever pressedagainst the cam while it is drawn along the cam in the movement of thenut, cutter-carrier bars borne by the machine-frame 180 apart and radialand perpendicular to the mandrelaxisand rotatableand endwise movable inrelation to their supports on the machineframe, and locking means forlocking the adjusted too ls and their supports in rela tion'to themachineatrame after their. adjustment in relation thereto.

23. Ina machine tool the combination of, a rotary traversing mandrel,bearings 1n which it is movable endwise as well'as rotatably, adriving-shaft, a train of' reducing gearing which forms an operativeconnection between said mandrel and drivingshaft and turns the former atan angular velocity lower than that of the latter, a wedge with two longfaces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and which1s at an angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in "fixed bearings, a driv ng-shaft forthe lead-screw, a train of reducing gearing which forms an operativeconnection between said vlead-v screw and the said'driving-shaft oftheleadscrew and turns the lead-screw at an angu-t lar velocity lower thano'fits'driving-shaft,

a nut mounted on the wedge and rotatable on it but held against endwisemovement in relation to the Wedge and threaded to the lead-screw, a camstationary alongside the line in which the nut moves with the wedge, alever extending from the nut and means to keep said lever pressedagainst the cam While it is drawn along the cam in the movement of thenut, two cutting-tools adjustably mounted in supports 0n themachine-frame and situated at opposite sides of the mandrel-end tominimize unbalanced cross-thrust on it, a saddle carrying eachcutting-tool and pivoted by one end of the saddle to the machine-frame,both saddles pivoted at one side of the mandrel and ex tended from theirpivots past the mandrel to its opposite side, clamps for the saddles andlocking means for looking the adjusted tools and their supports inrelation to the machine-frame after their adjustment in relationthereto.

24. In a machine tool the combination of a rotary traversing mandrel,bearings in which it is movable endwise as well as rotatably, adriving-shaft, a train of reducing gearing which forms an operativeconnection between said mandrel and drivingshaft and turns the former atan angular velocity lower than that of the latter, a wedge with two longfaces against one of which faces the tail of the traversing mandrelabuts, yielding means to press the said tail against the wedge, aslideway constituting an abutment along which the wedge slides and whichis at an angle to that one of the long wedge-faces against which themandrel tail abuts, a lead-screw in fixed bearings, a driving-shaft forthe lead-screw, a train of reducing gearing which forms an operativeconnection between said leadscrew and the said driving-shaft of thelead-screw and turns the lead-screw at an angular velocity lower thanthat of its driving-shaft, a nut mounted on the wedge and rotatable onit but held against endwise movement in relation to the wedge andthreaded to the leadscrew, a cam stationary alongside the line in whichthe nut moves with the wedge, a lever extending from the nut and meansto keep said lever pressed against the cam while it is drawn along thecam in the movement of the nut, two cutting-tools adjustably mounted insupports on the machine-frame and situated at opposite sides of themandrel-end to minimize unbalanced cross-thrust on it, a saddle carryingeach cutting-tool and pivoted by one end of the saddle to themachine-frame, both saddles pivoted at one side of the mandrel andextended from their pivots past the mandrel to its opposite side, clampsfor the saddles, a carriage interposed between one saddle and onecutter, to support the cutter adjustably along the length of the mandrelin relation to that saddle, guides on said saddle for the carriage thatare parallel to the mandrel-axis, and locking means for locking theadjusted tools and their supports in relation to the machine-frame aftertheir adjustment in relation thereto.

In testimony whereof I afiix m signature.

ARTHUR ERNEST J *RRAM.

